JPWO2006025488A1 - Damping material for machine parts and manufacturing method thereof - Google Patents

Abstract

It is a vibration-damping material for mechanical parts having a non-bonding interface that is in contact without being metallically bonded. The non-bonded interface is formed from the surface to a predetermined depth inside, and can have a structure that does not penetrate. In this case, the length of the non-bonded interface in the depth direction is preferably 20% or more of the thickness dimension in the same direction. The non-bonded interface may be formed so as to penetrate from one surface to another surface. The vibration damping material for machine parts is a vibration damping material for gears to form a gear having vibration damping characteristics, which is a ring-shaped or disk-shaped main body and teeth provided on the outer peripheral side surface or the inner peripheral side surface thereof. The non-bonded interface may be formed from at least one end surface in the axial direction of the main body portion.

Description

  The present invention relates to a material for processing parts used in automobiles, construction machines, industrial machines, etc., and particularly for machine parts capable of greatly improving vibration damping properties regardless of the material used. The present invention relates to a damping material and a manufacturing method thereof.

  In an automobile, a construction machine, an industrial machine, etc., each part is driven by power generated by an engine, a motor and the like. The parts used for them have various required characteristics depending on the parts, such as surface pressure resistance and bending strength, and materials suitable for satisfying them are selected and used.

  Most of these materials are alloys of Fe, Al, etc., but they have the drawback that the material itself is difficult to solve. That is, the parts made of these alloys easily propagate the vibration generated in the usage environment, and the parts have a limited ability to damp the vibrations, resulting in noise and reduced quietness. This may shorten the service life of the parts.

  For example, in recent automobiles, simply having excellent engine performance cannot satisfy the strict requirements of users, and a high level of quietness in the vehicle during driving is required. Came. In the case of automobiles, gear noise is one of the major causes of noise generation. However, gears that cause noise generation are generally carburized, and heat treatment distortion or the like adversely affects gear meshing. It has been found that the occurrence is the cause of noise generation. Therefore, while various technological developments aimed at reducing heat treatment distortion have been actively carried out, there has been a strong demand for the development of a technology for intercepting or reducing the generated sound and vibration.

  Taking this gear noise as an example, in order to prevent its occurrence, it is not impossible to consider a method of eliminating the heat treatment distortion by performing the finishing process again after the carburizing treatment. However, the finishing process therefor requires a great deal of cost. Also, it is technically possible to provide a damper mechanism on the gear or the unit itself that incorporates it, but due to the securing of space for that and the increase in the number of parts, cost constraints occur, and those The current situation is that adoption of measures has not progressed. Therefore, there has been a strong demand for technological development capable of ensuring the quietness that is satisfactory to the user even when the manufactured gear is used with the strain generated by carburization remaining.

  As a most direct improvement method for this problem, there is a method of manufacturing a component with a damping material and absorbing the vibration by the component itself. However, iron-based high alloys, pure Mg, Mg alloys, and Mn-Cu alloys are well known as damping materials known in the past, but it goes without saying that all are expensive. In addition, there is a problem that sufficient strength cannot be secured when used as a machine structural component. In addition, even if it is a composite steel plate with excellent vibration damping properties known in the steel plate field, when it comes to machine structural parts, especially power transmission parts, there are restrictions in terms of the shape of the steel plate, and the usable range is extremely small. . Therefore, there has been a strong demand for the development of a material capable of imparting excellent vibration damping properties regardless of the type of material without causing these problems.

  As a measure to improve the vibration damping property without using the special material having the excellent vibration damping property as described above, it has been a good practice to introduce an interface such as a crack, which is not intentionally metal-bonded, into the component conventionally. It is known and, for example, the techniques described in Patent Documents 1 and 2 are known.

  Among them, the technique described in Patent Document 1 forms a brittle layer (portion) in the material, and thereafter, thermal shock such as overheating and quenching is applied to intentionally generate cracks inside the material to suppress vibration. It is the one that tries to raise.

  Further, in Patent Document 2, a linear bead portion is formed at a required portion of a metal plate, and cracks generated in the bead portion attempt to enhance the vibration damping effect of the metal plate.

JP-A-52-147510 JP, 2000-35082, A

However, the above-mentioned conventional invention has the following problems.
In order to form a brittle layer inside the material, the invention described in the above-mentioned Patent Document 1 intentionally carburizes low carbon steel or uses high carbon steel which is a brittle material in advance, and quenches it. It is characterized by giving a thermal shock of.

  Therefore, if it is attempted to enhance the vibration damping property of a mechanical part using the technology of Patent Document 1, carburization is required even when it is used in a part where carburization is not required due to its strength, or high carbon steel is used. However, it is difficult to select a material that is originally considered optimal or a suitable heat treatment, and the selection of material and heat treatment method is significantly limited. There is a problem that it ends up.

  Further, as described in the specification, the invention described in Patent Document 2 utilizes quench hardening ability, and a crack is generated by using a metal plate having large quench hardening ability and high crack sensitivity. The feature is that a bead portion is formed at a portion to be caused to give a crack. Therefore, this technology inevitably cannot achieve its effect without using a metal plate having a high quench hardening ability, and in addition to the restrictions on the shape of the steel plate, the application range is greatly limited in terms of the material. There is a problem that it will end up.

  The present invention has been made for the purpose of solving the above-mentioned problems, has few restrictions in terms of material, is easy to select materials according to requirements, and can be widely applied to many machine parts, It is another object of the present invention to provide a vibration damping material for machine parts that can easily obtain excellent vibration damping characteristics.

  A first aspect of the present invention is a method of applying plastic working to a groove formed by plastic working and/or machining to reduce the inner space of the groove, or to the hole of the first material having a hole. A vibration-damping material for machine parts, characterized by having a non-bonding interface which is formed by a method of press-fitting a second material and is in contact without being metallically bonded.

  The present invention, as a result of earnestly studying so as to reduce the restrictions in terms of material and shape as much as possible, the following knowledge has been obtained, so that the restriction in terms of material is very small and the damping property is enhanced in a wide range. It has succeeded in providing parts.

(1) In the above-mentioned prior application patent, since cracks are generated by thermal shock, it is necessary to select a brittle material or to intentionally make it brittle, and the material is necessarily extremely limited. Had. However, we thought that the same damping effect could be obtained if a non-bonded interface could be created without thermal shock. Therefore, for example, as a result of intentionally imparting a non-bonding interface by utilizing plastic working and/or machining to evaluate the vibration damping property, even if the non-bonding interface is intentionally imparted by the working It has been found that a sufficiently large vibration damping property improving effect can be obtained depending on the shape of the interface. Further, the non-bonded interface can be generated by, for example, plastic working and/or mechanical working, as is known from the manufacturing method described later. Is obtained, and the limitation on the material can be made much smaller than that of the invention described in the above patent document.

(2) In the present invention, since the non-bonding interface is generated by, for example, plastic working and/or machining, it is easy to set the position of the non-bonding interface to a convenient position and shape for the mechanical component. .. Therefore, by providing a non-bonding interface at a position where the strength of the part is not a problem (= a position where high stress is not applied), it is possible to manufacture a mechanical part that has a non-bonding interface but has no problem in strength. Can be obtained.

(3) In order to secure excellent vibration damping properties, it is necessary that the gaps of the generated non-bonding interface are narrow and closed, and they are in contact with each other without metal bonding. The term "contact" as used herein includes a case where a non-contact portion is partially present in a microscopic view, and includes all cases where the contact is apparent at the interface.

A second aspect of the present invention is a method for producing a vibration damping material for mechanical parts having a non-bonding interface that is in contact without being metallically bonded,
A groove portion forming step of forming a groove portion which is a source of the non-bonded interface on the surface of the material by plastic working and/or machining.
A damping step for forming a non-bonding interface by applying a plastic working in a direction of reducing the inner space of the groove portion and bringing the facing inner wall surfaces into contact with each other. It is in the manufacturing method.

A third aspect of the present invention is a method for producing a vibration damping material for machine parts having a non-bonding interface that is in contact without being metallically bonded,
A first material having a hole and a second material having an outer shape that can be press-fitted into the hole are prepared, and the second material is press-fitted into the first material so that the hole A method of manufacturing a vibration damping material for machine parts, comprising a press-fitting step of forming the non-bonded interface at an inner peripheral wall position.

  According to these manufacturing methods, it is possible to reliably manufacture the excellent vibration damping material for mechanical parts described above.

  A fourth aspect of the present invention is a machine part characterized by being produced by processing the vibration damping material for machine parts. Machine parts made by applying the above excellent vibration damping material for mechanical parts as a material, for example, gears having teeth formed on the vibration damping material for mechanical parts described above have very excellent vibration damping properties. It has characteristics and is useful.

FIG. 6 is an explanatory view showing a shape immediately after groove processing, which is a state in which a non-bonded interface is being formed in Example 1. FIG. 3 is an explanatory view showing a state after non-bonding interface molding in Example 1. FIG. 5 is an explanatory diagram showing changes in the logarithmic reduction rate when the depth of the non-bonded interface is changed in Example 1. FIG. 6 is an explanatory view showing a vibration position at the time of evaluating vibration damping property of a spur gear in Example 2. Explanatory drawing which shows the 1st raw material in Example 4. Explanatory drawing which shows the 2nd raw material in Example 4. FIG. 13 is an explanatory view showing a spur gear of a type in which a pin is press-fitted in Example 4; Explanatory drawing which shows an example of the shape of a non-bonding interface. Explanatory drawing which shows an example of the shape of a non-bonding interface. Explanatory drawing which shows an example of the shape of a non-bonding interface. Explanatory drawing which shows an example of the shape of a non-bonding interface. Explanatory drawing which shows an example of the shape of a non-bonding interface. Explanatory drawing which shows an example of the shape of a non-bonding interface. Explanatory drawing which shows an example of the shape of a non-bonding interface.

Hereinafter, the content of the invention will be described in detail.
The molding of the non-bonding interface in the vibration damping material for mechanical parts of the present invention can be performed by performing at least the groove forming step and the compressing step as in the invention of the second aspect. The groove portion forming step is performed by plastic working, mechanical working, or a combination of both workings. Further, the compression step is performed by plastic working. As for the selection of these processing methods, an appropriate method can be selected according to the material, and it may be carried out cold or heated and hot.

  In particular, mechanical parts are often manufactured by forging because of their excellent productivity. Therefore, when the present invention is applied to a component that has been conventionally manufactured by forging, productivity is improved by redesigning the conventional forging process into a process in which the groove forming process and the compression process are possible. It is possible to manufacture mechanical parts with a non-bonded interface without significant reduction.

Further, the machining of the groove portion in the groove portion forming step can be performed by machining. In this case, the groove may be machined so long as the inner space of the groove is finally narrowed and closed. Therefore, the machining method is not particularly limited, and various means can be selected. However, when the groove portion is processed by plastic working such as hot forging and cold forging, it is easy and easy to form the V-shaped groove. Of course, it is also possible to form the V-shaped groove by machining.
In the case of utilizing forging, the groove portion forming step can be performed by forging using a die having a protrusion corresponding to the groove portion. Then, the shape of the groove can be controlled by selecting a desired shape as the shape of the protrusion.

  As described above, when the second side face manufacturing method is used, the non-bonded interface is formed from the surface to a predetermined depth inside, and may not penetrate. In this case, since it can be manufactured as a single component, it is possible to obtain a product having excellent dimensional accuracy and stability.

  In addition, the non-bonding interface to be generated has an effect of improving the vibration damping property in proportion to its size, and therefore it is necessary to generate a non-bonding interface that is large to some extent. That is, the larger the area of the interface, the greater the effect of damping the vibration. Specifically, the length of the non-bonded interface in the depth direction is preferably 20% or more of the thickness dimension in the same direction. The lower limit of the length in the depth direction is set to 20%, because if it is less than 20%, the vibration damping effect may not be sufficiently obtained. In addition, although the upper limit is not specified, even if the position of the non-bonded interface is selected and manufactured so that a large stress is not applied, there is a problem in strength depending on the shape of the part and the stress applied. When there is a possibility of occurrence, it is necessary to properly judge the upper limit of the interfacial depth depending on the applied component. As a guide, it is desirable to set it to about 90% or less. In order to obtain a sufficient vibration damping effect, it is desirable that the depth of the interface be 50% or more of the thickness dimension in the same direction.

  Further, as described above, the non-bonding interface is formed by first forming the groove part that is the source of the non-bonding interface by plastic working and/or machining, and then further plastic working in the direction of reducing the space inside the groove part. In addition, the inner space of the groove is processed to be as small as possible, and the almost non-bonded interface is apparently in contact with the formed non-bonding interface. Here, it is only necessary that the non-bonded interface finally come into contact with each other in appearance, so that the sectional shape of the groove to be processed first does not need to be particularly limited. It is possible to freely select and perform a shape that is convenient for processing (for example, in the case of performing by forging, processing is easy and there is no need to worry about the problem of die life to be used).

  After grooving, plastic working is performed in the direction to reduce the internal space of the groove, and the final formed interface is processed until the entire surface is in contact with the surface. Molding is completed. The contact on the interface mentioned here is just an appearance, and it is not necessary to strictly determine whether or not the entire surface is in contact. Therefore, even if there is a partial non-contact portion as a result of microscopic observation, it is not excluded from the scope of the present invention for that reason, as long as it is processed to a state where it is almost in contact with the naked eye. It is enough. By processing up to that state, the vibration damping property can be greatly improved. In addition, when the material is steel, the groove may be hot worked or heat treated at a temperature above the transformation point. As a result of processing in the direction of contracting to generate a contacting interface, it is possible to put a scale on the interface. In this case, due to the presence of the scale, the vibration damping effect at the non-bonded interface can be enhanced, and a more excellent vibration damping effect can be obtained.

As described above, one of the forms of the non-bonded interface is that which is formed from the surface to a predetermined depth and does not penetrate, but this is due to the formation of the groove portion by the plastic working and/or the mechanical working. Not only can it be formed by a combination of a process and a compression process by plastic working, but it can also be realized by partial press fitting by the manufacturing method of the third side surface described above. On the other hand, the non-bonded interface may be formed so as to penetrate from one surface to another surface. In this case, it can be realized by the press-fitting method which is the manufacturing method of the third side surface described above.
That is, a first material having a hole and a second material having an outer shape that can be press-fitted into the hole are prepared, and the second material is press-fitted into the first material to form the hole. By performing the press-fitting step of forming the non-bonding interface at the position of the inner peripheral wall of the part, it is possible to manufacture the vibration damping material for machine parts having the non-bonding interface that penetrates or does not penetrate.

  However, in this case, a very large residual stress is generated on the interface due to the press-fitting, which may adversely affect the improvement of the vibration damping property. Therefore, it is necessary to appropriately adjust the press-fitting margin. The hole provided in the first material may or may not be penetrated, but if not penetrated, the holes of the first material and the second material are made so that the press-fitting work can be smoothly performed. It is necessary to provide an air vent hole in either one.

  Further, it is preferable that at least one of the first material and the second material is subjected to a preliminary heat treatment for forming a scale on the surface before the press-fitting step. When the scale is present in advance, the obtained non-bonded interface enhances the vibration damping effect. This is clear from the examples described later.

  Next, when the vibration damping material for mechanical parts is used as a gear, its effect can be effectively utilized, and thus it can be used as a vibration damping material for gear for forming a gear having vibration damping characteristics. In this case, it has a ring-shaped or disk-shaped main body and a tooth profile forming portion provided on the outer peripheral side surface or the inner peripheral side surface thereof, and the non-bonding interface is at least one end surface in the axial direction of the main body section. It is better to be formed from.

  Gears are parts that naturally play a role of transmitting power of the engine etc. by meshing teeth, but the stress is not evenly applied to all parts of the gear, but the driving force is applied to the teeth. Since the load is concentrated, a large force is applied to a region apart from the tooth part, that is, in a gear with teeth machined on the outer or inner circumference, in a region other than the tooth part on the outer or inner circumference. Never. In some cases, a through hole may be partially used to reduce the weight. Therefore, the inventors of the present invention pay attention to the stress load state in such a gear, form a non-bonding interface at a position distant by an appropriate length from the region for processing the tooth, and manufacture the gear at the time of actual use. Similarly to the above, a fatigue test in which a driving force was applied was carried out. As a result, the effectiveness of the present invention was confirmed by understanding that the strength limit of the gear occurs due to the breakage of the tooth portion instead of the breakage from the non-bonded interface when the applied driving force is increased. It is a thing. Therefore, by manufacturing a gear using the vibration damping material of the present invention, it is possible to easily manufacture a gear having extremely excellent vibration damping properties.

  As described above, the non-bonding interface is generated, and the vibration damping property is considerably improved in the material stage before the tooth is processed. In that case, the vibration damping property is remarkably improved (the degree of the improvement will be concretely shown in Examples described later). Although the reason why the vibration damping property is significantly improved by machining into the shape of a gear is not clear, it is not clear that the teeth are machined on the outer circumference and the distance to the non-bonding interface is short at the tooth root. It can be considered as one of the reasons why. Further, gears are often carburized when it is necessary to obtain high strength, but the present invention can obtain excellent vibration damping properties regardless of the presence or absence of carburization.

The non-bonding interface is preferably formed in a ring shape. In this case, it is possible to reliably suppress the transmission of vibrations inside and outside the annular shape.
Further, in this case, the non-bonding interface can be formed in a circular shape. When the circular shape is adopted, the formation of the non-bonded interface can be facilitated.
Further, the non-bonding interface may be formed in an asymmetrical shape. The asymmetrical shape includes an isosceles polygonal shape, an irregular wavy shape, and various other shapes. In this case, the vibration damping effect can be expected to be further enhanced.

  Next, the vibration damping material for machine parts of the present invention will be described by way of examples in comparison with comparative examples. The chemical composition of the steel used as the test material is 0.21% C-0.32% Si-0.77% Mn-1.16% Cr-0.16% Mo-0.032% Al-0. This is a 011% N steel, and uses a JIS-SCM420H round bar that is easily available on the market.

  As shown in FIG. 1, a test material 1 having an outer diameter of 120 mm, an inner diameter of 25 mm, and a thickness of 20 mm of this SCM420H is prepared, and hot forging is performed to hit a cylindrical jig (not shown) on the surface as a substitute for a die. The width L (maximum) of the concentric circles with the material is 6 mm, and the depth d is 7 to 15 mm. Molded into 3 levels. Further, another test material made of the same component and having the same size was machined to have a similar groove shape (groove forming step).

  Next, for those that have been grooved by hot forging, without further cooling after groove processing, by further hot forging, processing is performed in the direction in which the space inside the groove is reduced (a circle that matches the inner diameter dimension). With the rod inserted, processing was applied until the space in the groove was as small as possible (compression step). As a result, in terms of appearance, the formed groove was in contact with the inner diameter side and the outer diameter side. Then, in that state, the processed test piece was cut and the cross section was observed, but as shown in FIG. 2, the non-bonding interface 50 which was virtually in contact with the inside was formed. Also, regarding the groove processed by machining, the groove was similarly processed by hot forging, and the section was confirmed by cutting, but it was apparently in contact with the inside at the interface as well.

  Next, the forging material formed by the hot forging was machined into a shape having an outer diameter of 96 mm, an inner diameter of 25 mm, and a thickness of 16 mm to obtain a vibration damping material for machine parts (gear damping material). The non-bonded interface diameter after machining was 50 mm after machining (test No. E11 as shown in Table 1 because the positions of the groove portions 5 were machined in three ways during the groove machining. ), 60 mm (test No. E12), 75 mm (test No. E13), and the depth of the non-bonding interface 50 was 4 to 13 mm. Further, a material round bar made of the same components and having no non-bonding interface, which is a comparative material (Test No. C11), was similarly machined to the same size. Then, the test piece after the machining was used to evaluate the vibration damping property described later.

  The vibration damping property is evaluated by suspending the ring-shaped material prepared as described above with two wires, vibrating the outer diameter end with a hammer, and measuring the vibration at the diagonal outer diameter end caused by the vibration. The measurement was performed using a laser displacement meter. Then, the logarithmic damping rate was calculated from the obtained vibration waveform, and the improvement level of the vibration damping property was evaluated by the value. The results are shown in Table 1 and FIG.

As is clear from Table 1 and FIG. 3, the test pieces (E11 to E13) in which the non-bonding interface 50 was introduced into the material by utilizing the plastic working and/or the mechanical working as in the present example had no non-bonding interface. It can be seen that the logarithmic attenuation rate is remarkably higher than that of the conventional material (C11) that does not have it at all, and the damping property is significantly improved by the formation of the non-bonded interface. In particular, it is understood that as the depth of the non-bonded interface is increased and the area of the interface is increased, the vibration damping property is improved. However, in the example in which the ratio of the depth of the non-bonding interface to the thickness is 25%, the damping effect is smaller than that of the comparative material. Therefore, in this experiment, the non-bonding interface having a depth of at least 30% or more is provided. It is possible to determine that it is preferable (however, as will be described later, the vibration damping effect is significantly increased when evaluated after processing into a gear shape, so the lower limit of the preferable range of the interface depth ratio is 20%. , If the shape of the member is different, the preferable depth range is considered to vary). In addition, it was clarified by this experiment that the performance of damping property also varies depending on the position where the non-bonded interface is formed. In this example, the larger the diameter of the non-bonding interface was, the better the vibration damping performance was obtained. However, it is considered that there is a difference in performance depending on the position of the noise source and the positional relationship of the non-bonding interface. Even with the component shape of this embodiment, the performance is not necessarily better when the non-bonding interface diameter is larger, and in reality, the optimum position for each component can be accurately determined after grasping the noise source. Thought necessary.
At least in the case of a gear, since the entire gear vibrates, it is considered that the damping capacity becomes larger when the non-bonded interface is present closer to the outer peripheral side where the amplitude is the largest.

  In the above-mentioned Example 1, the evaluation result of the vibration damping property in the state of the vibration damping material for machine parts (the vibration damping material for gears) before processing the teeth was shown, but as a matter of course, it was processed into a gear as an actual part. It is necessary to understand the impact of this. Therefore, as shown in Table 2, three types of materials (test Nos. E21 to E23) having a non-bonding interface depth of 13 mm and diameters of 50 mm, 60 mm, and 75 mm, which had a great effect of damping property in Example 1, were used. And a non-bonding interface depth of 3.5 mm, which is slightly shallower than the lower limit of the evaluation material of Example 1, and a non-bonding interface diameter of 60 mm (test No. E24) was used for module 3, number of teeth. Thirty spur gears 2 were produced. Then, similarly to the first embodiment, the position shown in FIG. 4 (end face excitation position S1, tooth face excitation position S2) is oscillated with a hammer in a state of being suspended on two wires, The vibration damping property was evaluated by the method of measuring the generated end face vibration of the diagonal tooth using a laser displacement meter. The reason for conducting the test with the material having the interface depth of 3.5 mm is to determine the lower limit interface depth at which the effect in the gear state is clearly recognized. The method of calculating the logarithmic decay rate is the same as that in the first embodiment. In addition, in order to make it possible to clearly compare the difference with the conventional product, gears with the same specifications without non-bonded interfaces made of the same material (SCM420H) (Test No. C21) and vibration-damping properties compared to steel. Was prepared at the same time as that prepared using spheroidal graphite cast iron FCD500 (Test No. C22), which is known to be excellent, and the same evaluation was performed. The results are shown in Table 2. Note that, in Table 2, as in the case of Example 1, the values are shown as ratios when the logarithmic attenuation rate (Test No. C11 of Example 1) at the material stage of SCM420H (without non-bonding interface) is 1. Indicated.

  As described above, according to the result of Example 1 evaluated before processing the teeth, the effect due to the formation of the non-bonded interface was 5.4 times at maximum (logarithmic damping ratio), but the state processed into the spur gear When evaluated by, the effect (logarithmic decay rate ratio) exceeding 200 times at maximum was obtained. It is considered that the reason why this remarkable effect was obtained is that the distance to the non-bonding interface became closer in the tooth bottom by the processing to the gear as described above, but it is also a simple disk shape. It is conceivable that the tooth shape of the spur gear has a shape suitable for improving the vibration damping property when the non-bonded interface is generated, as compared with the material. Further, a gear having an interface depth of 3.5 mm was also found to have a damping effect of about four times.

  Further, the effect of the present invention is also extremely large in comparison with FCD500 (C22), which is one of the spheroidal graphite cast irons that have been conventionally said to have superior vibration damping properties to steel. It could be confirmed.

  In Example 2, the spur gear in the as-machined state was used for the evaluation, but in actual gears, in order to satisfy the required strength, it is often carburized, and the effect of the treatment is You need to know exactly. Therefore, the same gear used in Example 2 was used as it was, carburized at 930° C. for 4 hours, and the same vibration damping evaluation was performed. In addition, in the above-mentioned Example 2, in order to evaluate the vibration damping property, the material to be evaluated was vibrated and evaluated in a state where the side surface of the gear was in contact with the wire when suspended by the wire. In order to reduce the effect of the above, the evaluation was performed in a state where the side surface did not contact the wire. The evaluation was performed both before and after carburization. The results are shown in Table 3 (measurement results at the end face excitation position S1 in FIG. 4) and Table 4 (measurement results at the tooth face excitation position S2 in FIG. 4). The numerical values shown in Tables 3 and 4 are the logarithms of the respective gear test pieces when the logarithmic decrement of the spur gear (before carburization, test No. C21) of the non-bonded interface of SCM420H which is a comparative material is 1 The attenuation rate is displayed as a ratio.

  As is clear from Tables 3 and 4, it can be seen that the effect of forming the non-bonded interface of the present invention is a large effect of improving the damping property regardless of the presence or absence of carburization. Although the cause is not clear, judging from the results obtained, there was a tendency that after carburizing, the effect of improving the damping property by the non-bonded interface was further increased. Moreover, as a result of changing the method of suspending the wire at the time of evaluation, the difference in the vibration damping property between the gear of the present invention and the gear of the comparative material became larger, and a remarkably large improvement in damping rate of up to about 1000 times was confirmed. It was possible (E43). Furthermore, in the evaluation before machining the teeth, when the interface depth was 3.5 mm (E34, E44), almost no improvement in vibration damping property could be confirmed, but the effect is greatly improved by machining into gears. However, like the results of Table 2, it was confirmed that an effect of about four times the logarithmic attenuation rate was obtained as compared with a gear without an unbonded interface.

In this example, as a test piece, a spur gear having an unbonded interface formed by press fitting was prepared and evaluated.
The test piece is a spur gear having a thickness of 16 mm, a module 3, a number of teeth of 30, and an inner diameter of 25 mm, as in the case of the second embodiment described above. The second material 22 on the inner diameter side was press-fitted into the through hole 210 of the material 21 of No. 1 and then machined to form the teeth and the like. In addition, as shown in FIG. 7, some of them have a specification in which through holes 6 are provided at six positions in the circumferential direction of the non-bonding interface 5 in the obtained spur gear 2 and the pins 61 are press-fitted therein. Further, as shown in FIG. 7, the teeth 29 are processed so that the teeth 29 are located on the center and the extension line of the through hole 6. In addition, in the figure, the teeth are partially omitted and the outer peripheral ends thereof are shown by wavy lines.

  In order to change the non-bonding interface 5, as shown in FIG. 6, the second material 22 has three outer diameters D2 of 45.09 mm, 60.11 mm, and 75.15 mm (all inner diameters D1 are 25 mm). Prepared. Further, as shown in FIG. 5, as the first material 21, three types of the inner diameter D3 of the hole 210 of 75.00 mm, 60.00 mm, 45.00 mm (all outer diameters D4 are 95.8 mm) were prepared. .. Further, the chamfered portion 225 is provided at the outer peripheral corner of the second material 22, and the chamfered portion 215 is provided at the inner peripheral corner of the first material 21.

Further, as the more specific method for producing the test piece, the following two types were adopted: a cold press-fitting method and a scale press-fitting method.
In the cold press fitting method, two parts (the first material 21 and the second material 22) are press fitted at room temperature.
In the scale press-fitting method, the two parts to be press-fitted are heated to 900° C.×1 hr to have a scale on the surface, and then cold-press fit. The scale thickness was about 100 μm.

In the case of the scale press-fitting method, a part of the scale fell off from the surface during press-fitting, but a part of the scale could be press-fitted while remaining on the non-bonding interface as it was. After press-fitting, the vibration damping property was evaluated. The vibration damping evaluation method was the same as in Example 3.
Table 5 shows the types of test pieces produced and the test results. The comparative product (test No. C51) is the same as the comparative material 1 (C21) in Example 2.

  As is known from Table 5, the non-bonded interface generated by press-fitting improved the vibration damping property by 1.3 to 8.5 times in logarithmic damping rate. In particular, the ones in which the area of the interface was increased by inserting the pin (E53, E56) showed a higher vibration damping property improving effect than the other test products. Further, when the scale was attached to the surface in advance and press-fitted (E51, E54), the vibration damping property was improved as compared with the case where the scale was not attached. From this result, it is understood that the vibration damping property is improved when the scale is present at the interface.

  That is, when the non-bonding interface is formed by press fitting, the scale is narrowed at the non-bonding interface, because the damping property is improved as compared with the case where the scale does not exist. It is desirable to manufacture by such a process.

  However, in comparison with the spur gear prepared by forming the non-bonding interface by forging shown in each of the above-described examples, when the non-bonding interface is formed by press fitting, the damping effect is reduced and the non-bonding interface is reduced. Neither did the tendency that the larger the diameter of the interface was, the more the vibration damping property was improved. Also, press-fitting is inferior to forging in productivity. Therefore, it is desirable to form the non-bonded interface by forging as much as possible. However, if the merit of die forging cannot be sufficiently obtained because the parts are large and the number of products to be produced is small, it is possible to select the vibration damping property improvement by press fitting.

In each of Examples 1 to 4 described above, the shape of the non-bonding interface was all circular in order to facilitate the experiment. However, in the present invention, the non-bonded interface is not limited to the circular shape as long as it can enhance the vibration damping property, and it is of course possible to have another shape.
For example, as shown in FIGS. 8 and 9, when a vibration damping material for machine parts or a disk-shaped member 6 as a machine part is assumed, regular polygonal non-bonding interfaces 51, 52 can be formed. Further, as shown in FIGS. 10 and 11, the non-bonding interfaces 53 and 54 may be asymmetrical polygons of unequal sides. In particular, when a non-bonding interface is formed by press-fitting into a through hole, a non-bonding shape can be obtained by using a shape other than a circular shape, such as the polygon described above, in order to enable stable torque transmission. It is necessary to prevent the parts on the outer diameter side and the inner diameter side from slipping at the interface. Examples of other non-bonding interface shapes are shown in FIGS. FIG. 12 is an example in which the non-bonding interface 55 is provided in the shape of a rectangular spline. FIG. 13 is an example in which the non-bonding interface 56 is provided in an involute spline shape. FIG. 14 is an example in which the non-bonding interface 57 is provided in a serration shape.

Further, as shown in FIGS. 10 and 11, when the non-bonded interfaces 53, 54 of the isosceles polygon are adopted, the damping property is improved as compared with the case of using the isosceles polygon for the following reason. it is conceivable that.
That is, when teeth are formed at equal intervals on the inner diameter side or the outer diameter side like a gear, the meshing of the gear pair has a specific frequency according to the rotation frequency and the number of teeth. Also, torque similarly occurs at a certain frequency. In the case of an equilateral polygonal non-bonded interface, the non-bonded interface receives the torque and vibration from the meshing tooth surface periodically, but the non-bonded interface also receives them at a cycle according to the number of angles, so the vibration damping effect can be reduced. There is a nature. On the other hand, if it is an unequal-sided interface, the interface for vibration damping has an indefinite period, so that the damping effect can be expected to be further improved in an actual gear drive environment.

As shown in Examples 1 to 4, it was confirmed that the formation of the non-bonded interface has a great effect on the vibration damping property, but the molding of the non-bonded interface greatly reduces the strength and causes a trouble in use. Therefore, it is actually difficult to use as a mechanical part. Then, among the above-mentioned test pieces, using a spur gear (930° C.×4 hr carburized, E42 of Example 3) which is a test piece having a non-bonding interface diameter of 60 mm and a non-bonding interface depth of 13 mm, The strength of the gear was evaluated by performing a root bending test.
As a result, even in the case of a gear processed using a material having a non-bonding interface as in the present invention, it does not break from the non-bonding interface, and when the limit stress is exceeded, It was confirmed that the breaking caused a strength limit. It is presumed that this is because a large stress is applied only to the teeth on the outer peripheral portion, and a large stress load is not applied to the position where the non-bonded interface is formed. At the same time, a test was also performed on a gear of the same specification manufactured using a material having no non-bonding interface at the same time as the conventional one, but the maximum stress at which tooth breakage does not occur is the same as in the present invention. No significant difference was observed with the value evaluated for the gears that it had.

  From this result, there is a portion to which a large stress is applied and a portion to which a large stress is not applied, and even when the non-bonded interface is introduced as in the present invention, the interface is a portion where a large stress is not applied in the mechanical part. When molded into, it was revealed that there is no extreme change in strength as compared with conventional mechanical parts that have no non-bonded interface.

  As described above, the vibration damping material for mechanical parts according to the present invention has the non-bonding interface not metallically bonded formed by plastic working and/or machining, or press-fitting. The vibration damping property can be significantly improved as compared with a material having no interface. Especially when processed into actual parts such as gears, it has a remarkable effect that it is possible to obtain more excellent vibration damping property than the material before processing, and the effect is typical surface. It can be obtained regardless of the presence or absence of a carburizing treatment which is a hardening treatment.

  Further, the present invention is characterized in that the non-bonding interface is formed by plastic working and/or machining or press fitting, so that the non-bonding interface can be formed as long as these processes are possible. Is much less than the conventional case where cracks are generated by using thermal shock. Therefore, it is possible to select the optimum material according to the part to be used and the required characteristics.

  Furthermore, when forming a non-bonded interface by mechanical processing, plastic working, or press-fitting, as a matter of course, it is possible to freely select a part that is convenient for mechanical parts and form the non-bonded interface, so that a large stress is applied. By selecting a portion where is not loaded and forming the non-bonded interface, it is possible to significantly improve the vibration damping property with almost no decrease in strength as compared with the conventional mechanical part.

Claims (13)

By a method in which a groove formed by plastic working and/or machining is subjected to plastic working in a direction to reduce the space inside the groove, or by a method in which a second material is press-fitted into the hole of a first material having a hole. A vibration-damping material for machine parts, which has a non-bonding interface that is formed and is in contact with each other without being metallically bonded. The vibration damping material for machine parts according to claim 1, wherein the non-bonding interface is formed from the surface to a predetermined depth inside and does not penetrate. The vibration damping material for machine parts according to claim 2, wherein the length of the non-bonded interface in the depth direction is 20% or more of the thickness dimension in the same direction. The vibration damping material for machine parts according to claim 1, wherein the non-bonding interface is formed so as to penetrate from one surface to another surface. The damping material for machine parts according to any one of claims 1 to 4, wherein the damping material for gears is a damping material for gears to form a gear having damping characteristics, and has a ring-shaped or disc-shaped main body portion, For a machine part, which has a tooth mold forming planned portion provided on the outer peripheral side surface or the inner peripheral side surface, and the non-bonding interface is formed from at least one end surface in the axial direction of the main body section. Damping material. The vibration damping material for machine parts according to any one of claims 1 to 5, wherein the non-bonding interface is formed in a ring shape. The damping material for machine parts according to claim 6, wherein the non-bonding interface is formed in a circular shape. The vibration damping material for machine parts according to claim 6, wherein the non-bonding interface is formed in an asymmetric shape. A method for manufacturing a vibration damping material for a machine part having a non-bonding interface that is in contact without being metallically bonded,
A groove portion forming step of forming a groove portion which is a source of a non-bonded interface on the surface of the material by plastic working and/or machining.
A damping step for forming a non-bonding interface by applying a plastic working in a direction of reducing the inner space of the groove portion and bringing the facing inner wall surfaces into contact with each other. Production method. The method for manufacturing a vibration damping material for machine parts according to claim 9, wherein the groove forming step is performed by forging using a mold having a protrusion corresponding to the groove. A method for manufacturing a vibration damping material for a machine part having a non-bonding interface that is in contact without being metallically bonded,
A first material having a hole and a second material having an outer shape that can be press-fitted into the hole are prepared, and the second material is press-fitted into the first material to form the hole. A method of manufacturing a vibration damping material for machine parts, comprising a press-fitting step of forming the non-bonded interface at an inner peripheral wall position. The mechanical component control device according to claim 11, wherein at least one of the first material and the second material is subjected to preliminary heat treatment for forming a scale on the surface before the press-fitting step. Manufacturing method of vibration material. A mechanical component, which is produced by processing the vibration damping material for mechanical component according to any one of claims 1 to 8.

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